<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>

    <button id="btn">10</button>

    <script>

        var oBtn = document.getElementById('btn');

        var t = setInterval(function () {
            oBtn.innerHTML--;
            if (oBtn.innerHTML == 0) {
                clearInterval(t)
            }
        }, 1000)

    </script>

</body>

</html>